Effect of Pretreatment in The Analysis of Mineral Water

Samples containing more than 10mg/L of Mg²⁺ and/or 20mg/L of Ca²⁺ must be pretreated, because those divalent cations form complexes with the eleuent and give rise to broad peaks which interfere with the analysis. For pretreatment,samples are passed through a pretreatment cartridge packed Na⁺ type cation exchange resin. This replaces the divalent cations in samples by Na⁺ and removes the interferring peaks.

(Pretreatment with the cartridges packing Na⁺ type cation exchange resin)
1. Rinse the cartridge with 3mL of methanol and 3mL of H₂O separately.
2. Load 3mL of the sample onto the cartridge.
3. Waste 1mL of the first elution.
4. Collect 2mL of following elution.


Sample : Mineral water (Water), 100micro-L
1. HCO₃^-
2. Cl^-
3. NO₃^-
4. SO₄^2-

Column       : Shodex IC SI-90 4E (4.0mmID*250mm)
Eluent       : 5mM p-Hydroxbenzoic acid + 5.3mM N,N-Diethylethanolamine aq.
Flow rate    : 1.0mL/min
Detector     : Non-suppressed conductivity
Column temp. : 25deg-C